Fig. 4From: Emphysema quantification using chest CT: influence of radiation dose reduction and reconstruction techniqueEffect of different thresholds (a) and percentiles (b) on emphysema quantification. For FBP at reduced dose a lower threshold is more appropriate, while with HIR and MIR a higher HU threshold should be used. With the percentile quantification method, FBP at reduced dose requires a higher percentile while with HIR and MIR a lower percentile should be used to achieve the same results as with FBP at routine dose. FBP filtered back projection, HIR hybrid iterative reconstruction, MIR model-based iterative reconstructionBack to article page